DESCRIPTION: The objective of this project is to develop a Magnetoencphaloic (MEG) assay of the effects of marginal or overt callosal hypoplasia associated with Fetal Alcohol Syndrome (FAS) and Prenatal Exposure to Alcohol (PEA). The long term goal is to develop, using MEG, a set of detection methods to identify ambiguous cases of FAS or PEA. The study will involve a well characterized population of FAS and PEA children (ages 11-16) already undergoing a long term study, including MR scans, an appropriate selection of age matched normal controls. The proposed project will involve MEG and simultaneous EEG, with subjects involved in a visual letter judgement task, which will compare single hemifield and two-hemifield letter presentions. Behavior performance differences and reaction times will be compared with EEG and MEG event related responses (latencies and distributions), for evidence of callosal agenesis or functional impairment. Mid-sagittal MR slices-will be evaluated to seek evidence of callosal hypoplasia. The same MEG data sets will be evaluated for changes in the distribution of spontaneous alpha band suppression in visual areas, associated with attention to the visual task. The data analysis will also involve MEG dipole modeling to localize evoked sources in visual cortex. These measures can then be applied as an instrument to assess abnormal function in correlated with cognitive performance and development of FAS/PEA subjects in longitudinal studies.